Several RNA viruses have segmented genomes where the presence of more than one RNA molecule is required for replication of the virus, is divided between two RNA components each of which are encapsulated separately. Both RNA components have polyadenylate sequences at their 3'-termini. Employing methods that selectively bind RNA fragments that contain poly(A), we are characterizing the sequences adjacent to the poly(A) termini of the two RNA components. The complementary strands from replicative double stranded forms will also be tested for the presence of poly(U) tracts. A study of controlled degradation of the viral components is planned. This should determine the degree that RNA-protein interactions are involved in virus structure and possibly elucidate the mechanism of the uncoating of the virus upon cell entry.